http://www.sourninja.com/dualwield/ I've pre-ordered one of these for my Xserve as freeing up a PCIe slot will make my life a lot simpler, but they would be a cheap and flexible option for iMac owners with flaky graphics or just after a graphics boost, even even just as an insurance policy. I only stumbled across them yesterday, and unfortunately they're on Kickstarter with only a few hours left to go and a handful of backers. Any iMac or Xserve owners with a penchant for tinkering should be tempted to get one. I hope these don't end up just being vapourware...